Unexpected Bismuth Concentration Profiles in MOVPE GaAs1-xBix Films Revealed by HAADF STEM Imaging
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چکیده
Recent interest in the growth of GaAs1-xBix semiconductor alloys with controlled Bi concentration has been stimulated by the sensitivity of the bandgap energy and valence band structure to Bi concentration, x. These sensitivities offer the possibility to engineer both the band gap and band offsets at junctions to improve the performance of devices. Realization of this potential, however, requires development of thin film growth techniques that coax Bi atoms into a GaAs lattice in which they are insoluble. Electron microscopy studies are critical to the materials characterization that is needed to understand and then control how Bi atoms, with large atomic radius and electronegativity differences relative to the As atoms they must replace, are distributed within the metastable GaAs1-xBix materials and, ultimately, device structures grown.
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تاریخ انتشار 2014